Date: Wed, 20 Oct 2004 10:49:08 +0800 From: Xin LI <delphij@frontfree.net> To: Mike Jakubik <mikej@rogers.com> Cc: freebsd-current@freebsd.org Subject: Re: FreeBSD 5.3b7and poor ata performance Message-ID: <20041020024908.GA3797@frontfree.net> In-Reply-To: <4259.192.168.0.188.1098217092.squirrel@192.168.0.188> References: <41715E7F.7060509@ng.fadesa.es> <20041018100045.f8koww0skcco0woo@www.sweetdreamsracing.biz> <4173D66F.6010200@DeepCore.dk> <4173F2E9.7010407@ng.fadesa.es> <417406E3.9010706@DeepCore.dk> <4174FD04.8040000@ng.fadesa.es> <20041019104525.ikgw8kcw8sw480os@www.sweetdreamsracing.biz> <4129.192.168.0.188.1098211592.squirrel@192.168.0.188> <20041019200908.GA655@frontfree.net> <4259.192.168.0.188.1098217092.squirrel@192.168.0.188>
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--NzB8fVQJ5HfG6fxh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, Mike On Tue, Oct 19, 2004 at 04:18:12PM -0400, Mike Jakubik wrote: > Xin LI said: >=20 > > Unfortunatelly I can reproduce similiar problem when using Ultra320 und= er > > mpt(4) and a version of Adaptec's SCSI card (maybe aic, or something el= se, > > which I have to go to my office to find out). Additionally the problem= is > > not FreeBSD specific, with a Linux installation, it shows poor performa= nce > > too. (No RAID configuration, though). > > > > I found that block size does influence performance greatly. With a blo= ck > > size of 131072 I got peak read performance at about 70MB/s, but that's > > all. > > I did not have the necessary knowledge at the time I have did the test > > last > > month, so I got only the result and thought that I have made something > > wrong and hoped someone to correct me with no luck :-( >=20 > Hrm, i tried your block size, and the performance is even worse: >=20 > # dd if=3D/dev/da0 of=3D/dev/null bs=3D131072 count=3D2000 > 2000+0 records in > 2000+0 records out > 262144000 bytes transferred in 8.688651 secs (30170852 bytes/sec) You may want to try other block sizes, like 65536, 262144, 524288, 1048576 or so. The peak performance block size depends heavily on hardware... Cheers, --=20 Xin LI <delphij frontfree net> http://www.delphij.net/ See complete headers for GPG key and other information. --NzB8fVQJ5HfG6fxh Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (FreeBSD) iD8DBQFBddIk/cVsHxFZiIoRAkBbAJ9cR9SqUZNJNm8A0qtraT8F5SsCUQCeMe09 rZHLAnyasnMj9noRe7R8sNs= =u4Sc -----END PGP SIGNATURE----- --NzB8fVQJ5HfG6fxh--
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